obex: Opening in the floor of the fourth cerebral ventricle through which spinal fluid enters the center of the spinal canal.

 

oblique X-ray: X-rays taken from an angle that allows for a direct view through the nerve canal or foramina. 

 

obturator: An opening in the low pelvis.

 

occipital condyle: The joint at the base of the skull that articulates with the upper part of the first cervical vertebra.

 

occipital muscles: Muscles behind the back of the neck that reach the back of the skull.

 

occiput: The back of the skull.

 

operating microscope: A type of microscope that is used for surgery, typically spinal surgery, that provides a 3-dimensional magnified view with superior lighting.

 

opiates: Narcotic medications.

 

OPLL (ossification of the posterior longitudinal ligament): An abnormal bone formation within the spinal canal, along the dura that is anterior to the spinal cord and posterior to the vertebrae. 

 

osteoblast: A type of cell that generates new bone.

 

osteoclast: A type of cell that can digest or destroy bone.

 

osteoconductive: material that helps provide a medium for bone formation.

 

osteocyte: A bone cell.

 

osteogenesis: The formation of new bone.

 

osteogenic proteins: Proteins that promote the formation of new bone.

 

osteoinductive: Proteins and materials that encourage the body to produce osteogenic proteins. 

 

osteomyelitis: An infection of bone.

 

osteophyte: A bone spur.

 

osteoporosis: Softening of bone due to loss of calcium, typically with age.